Most people in the know have been aware of 64-bit computing for quite some time. After all, the 64 in Nintendo 64 (released in 1996 - almost 12 years ago) does indeed stand for 64-bit. One might be surprised, however, to learn that the 64-bit architecture has actually been around since the 60s when IBM developed their 7030 Stretch. Why, after so long, is hardly anyone running a 64-bit personal computer yet? Sure, most people (myself included) have 64-bit ready hardware. In fact, it's difficult to find a true 32-bit CPU these days. All that's needed is a 64-bit OS. For those of you using one of the *nix varieties, or Leopard, you already have that and kudos to you. For the rest of the world, who apparently are still running Windows XP, they're stuck at 32-bit and probably don't even know there's XP and Vista x64. Despite all this, 3 years ago, PC World was ready to usher in the new era of 64-bit computing. What happened?

To get to the bottom of this, and to find out if you should be seeking out a 64-bit OS, one has to look at what exactly it means for an OS to be 32-bit vs. 64-bit. The terms refer to the lengths (in binary of course) of various data fields, such as integers, memory addresses, etc. A 32-bit OS cannot hold in its memory any data longer than 32 bits without splitting it up into multiple compartments. Because of the way CPUs address memory so that programs and the hardware know where data is, there is an absolute maximum amount of memory that can be used by the OS: 2^32 addresses or 4 GB of memory for 32-bit OSes and 2^64 or a truly impressive and astonishing 16 exabytes of memory (that's 4 billion times as much, if you're unaware of the scales) for 64-bit OSes.

So, it's clear, if you need more than 4GB of memory, you should definitely be running a 64-bit OS, but then again you probably already are. 4GB is currently more than enough for a vast array of computer applications. Even memory-hogging games simply can't use up 4GB. Most systems with more than 4GB are servers or other hardcore systems, which tend to run *nix and also tend to already be using 64-bit for a while. How about if you, like us mere mortals, have at most 4GB? Is there a reason to switch, or a reason not to?

Let's start with the reasons to switch. First, 64-bit is definitely the way things are going. It's been moving slowly, but definitely surely in that direction for a number of years and more and more people are coming out with 64-bit software. Second, you can run 32-bit software on a 64-bit OS with no performance loss, so even if your favorite program isn't available in a 64-bit version yet, it won't matter. Third, when a 64-bit version exists, it runs faster and uses memory more efficiently. These 64-bit versions will come along fast and furious, as making a 64-bit version essentially involves a few minor changes for the program to compile in a 64-bit compiler.

But then, there are quite a few reasons not to. First, while 32-bit applications will run fine, 32-bit drivers will not and hardware manufacturers are being quite slow to get drivers out. This is obviously going to be less of an issue as time goes on, but it can be a game-ender if your printer or scanner or worse DVD-RW won't work. Second, 16-bit applications won't run on either XP or Vista x64 without making use of an emulation system. Third, there aren't many 64-bit programs available.

What programs are available? really not very many (read the whole thread to get updates). Games are pretty highly represented, which is unsurprising given their high memory usage. Notably absent are Adobe products, which would seriously benefit from a 64-bit upgrade, Microsoft Office, many antivirus and security products (some use 64-bit engines, but 32-bit front-ends, which makes sense really).

So, where do things stand? If you need a lot of memory and you know all your peripherals have driver support, go right ahead. You won't see a performance drop on basically anything, and you'll see significant performance gains in some areas, depending on the applications you use. On the other hand, if your peripherals come from a questionable Chinese company that hasn't updated its driver page in 2 years and you can't imagine needing more than 4GB of memory, there's just not enough performance gain yet.

64-bit is definitely a thing to keep your eye on, however.